Sean McGowan has wanted to be an actor since elementary school. With the support of his family, friends and teachers, the 21-year-old Valley Stream resident with Down syndrome is pursuing that dream.

Last month, McGowan played the lead role of Peter in the New York University Educational Theatre Department’s production of “Peter and the Star Catcher.” The intimate, 80-seat black box theater was sold out for all nine performances, which included actors with and without disabilities.

“It felt amazing,” McGowan said. “I was like the star of the show.”

When he was a teenager, his mother, Debbie, saw him struggling in their local school district in Valley Stream and transferred him to Rockville Centre, a district that prides itself on being inclusive and providing educational options and extracurricular activities for students with different needs.

“I’ve always been a firm believer in following their dream, whatever that is,” Debbie said. “As a parent, you can’t leave one stone unturned. You have to follow through on everything.”

One extracurricular activity at South Side seemed perfect for Sean: Centre Stage, a drama club that combines students who are typical learners and students who have developmental disabilities. He joined in 2013, and was “a hit from the beginning,” Debbie said.

“They mixed kids [of different abilities] and taught us how to be on stage and perform,” Sean said. “I’m kind of happy, but kind of sad because I miss all my friends” from Centre Stage.

McGowan added that Centre Stage taught him and his classmates to be “self-directed” by practicing patience and proper etiquette on and off stage during a production.

He had Centre Stage roles in “Neverland” (2013), “Glee” (2014), “Into the South Side Woods” (2015), “Calendar Catastrophe” (2016), “Greetings from South Side” (2017) and this year’s “Centre Stage the Musical: 10 Years in the Making,” in which he performed a duet of “You’re the One That I Want” from “Grease” with Samantha Gross.

He has performed with Camp Anchor’s drama program and Into the Wings, a community theater group in Valley Stream. McGowan is also involved in Backyard Players & Friends, a Rockville Centre organization that provides programs for people of all abilities, including theater games.

“These are the kinds of opportunities that need to be more readily available to people of all abilities,” said Ellen White, founder of the Backyard Players, referring to McGowan’s role in the NYU production. “We are so proud of Sean, and our wish is for all to be given a chance to chase their dreams free of the limits placed on their abilities — to be included in things as simple as dreams.”

Earlier this year, a few months after McGowan graduated from South Side, his friend and mentor, creative arts therapist Adam Stevens, told Debbie and her son about the auditions at NYU.

Debbie recalled speaking with Stevens on the phone, noting to him that Sean couldn’t read well. “Don’t worry about that,” she recalled him saying. “They expect people of different abilities and disabilities, so we’ll work with it.”

McGowan traveled to Manhattan for an audition, two callbacks and then rehearsal after rehearsal for six weeks. The director had cast him as Peter, a “happy, amazing” moment, McGowan said.

“Sean has such a passion and it shows, so I think that’s what helped him land this,” his mother said.

Stevens was the show’s accessibility consultant. He read McGowan lines at the audition. After being cast as adult Peter, McGowan was paired with actor Michael Manzi, who played Peter as a boy.

McGowan worked closely with School of Rock in Rockville Centre to learn many of the songs he sang in the show. He also credited the show’s director, Amy Cordileone, for her guidance. The experience gave McGowan confidence, and traveling into the city increased his independence and provided new friends, he said.

“I was blown away by how great [the show] was,” Debbie said. “They really did an amazing job.”

She added that she was touched by the performance and how people of all abilities worked with McGowan to show off his talent.

“I think it’s breaking down walls that have to be broken down because these kids really have so much to offer,” Debbie said. “I’m happy for the audiences who got to see that there’s a lot of ability out there. That’s what we need to focus on — the ability and not the disability. They’re all pretty capable of a lot of things.”